GT league is useless as it is, and the arcade mode should not have been called the arcade mode.
PD should have made a campaign that includes
-mandatory driving school and circuit experience
-Challenges
-Customizable league races with possibly of creating custom championships, with BOP etc
The GT league is too hard for those who suck, and to easy for those who don't.
For each race there should be a choice "easy, intermediate, difficult", with credits that reward difficulty levels.
Obviously GT sport was aimed to online only players, but PD realized to late that a big part of their players are too bad, too shy, not interested, or not willing to deal with dirty drivers (...), and therefore not interested in online racing. The GT league is just a bandaid to fix the hemorrhage of offline players.
So yeah the GT league is necessary but also completely useless at the same time.
[im also curious about how PD would have expected the players to get 20M without the GT league, and why did they add cars that you basically can't race ever in the sport mode if their aim was online racing only ?]